WASHINGTON - For a man who spent 12 years in the Senate, Chuck Hagel will find himself with few close allies when the Armed Services Committee takes up his nomination to be secretary of defense this month.

His three closest friends from his years as a Republican senator from Nebraska, 1997-2009, are either no longer members or in no position to help. One is Vice President Joe Biden. Another, Richard Lugar of Indiana, left this month after being defeated for re-election in a GOP primary. The third, Sen. John Kerry, D-Mass., faces his own proceedings to be secretary of state.

'Bitterly contentious'

Of the senators who will sit in judgment when hearings begin at the end of the month or in early February, 42 never served a day with Hagel. The ones who remain include powerful Republicans who clashed repeatedly with him over what was the singular issue of the time: the U.S. invasion of Iraq.

And in Washington, apostasy from within a party can leave far deeper scars than the routine clashes between the parties.

"The debate over the Iraq war was bitterly contentious," said former Sen. Bob Kerrey, D-Neb., who like Hagel is a Vietnam veteran. "He made friendships with Democrats and Republicans, but some of them were certainly damaged by the Iraq war debate."

Even in the current environment, a president's nominee with a Senate pedigree is supposed to have an inside track to confirmation. Kerry's confirmation is thought to be a bipartisan certainty, and his views on Iraq were no less vocal than Hagel's.

But Hagel was no ordinary senator serving at an ordinary time. His outspoken, brusque style endeared him to television talk show bookers, but he was not known as a legislator or a dealmaker. An intense focus on foreign policy placed him in the heart of a bipartisan foursome on the Senate Foreign Relations Committee that included Biden and Lugar, who alternated as the panel's chairman and ranking minority member, and Kerry.

'His overall attitude'

But those same traits alienated the more hawkish leaders of the Senate Armed Services Committee, including a natural Republican ally, Sen. John McCain, a Vietnam War hero, as well as Sen. Lindsey Graham, R-S.C. -- both of whom have been critical of his nomination.

"My biggest concern is his overall attitude about the United States, our role in the world, particularly in the Middle East, and whether we should reduce the Pentagon further," McCain told CNN on Tuesday.

Republican opponents say their positions are not rooted in the personal. "It's not a matter of personalities," said Sen. John Cornyn, R-Texas. "Chuck Hagel is an honorable man."

But supporters and some detractors say Hagel's style cannot help but shape his nomination's reception in a Senate more deeply political than the one he left four years ago. "This is a person in public life prepared to offer his honest objections, to give his opinions," Lugar said, "and to do so without looking over his shoulder at potential political contributions or the people who might run a primary campaign against him, which is the overwhelming sentiment of so many today in the Senate."